Klipsch Icon XF-48 active stereo speakers.

Klipsch's XF-48: Strong, Slim, and SexyXP-48KlipschXF-48Klipsch began making high-performance speakers well before the advent of the transistor, so when it unveils an all-new flagship design, the world pays attention. Topping the company's Icon line, the XF-48 is a departure for Klipsch for several reasons. It's slim and very well dressed, with a gloss-lacquer finish and compound-curving "cheekbone" angles to its aluminum enclosure. It has a pair of oval passive-radiator diaphragms (no doubt in the interest of the aforementioned slimness). And it boasts an all-new horn-tweeter design. Most unusual of all, the XF-48 is an active full-range speaker - which means that all of the necessary amplification, custom tailored to its woofers and tweeter, is contained within the speaker itself. Any engineer (or Vulcan) will tell you that active is the only logical speaker design. The advantages are many. Without wasting silicon (or dollars) on excess, you can ensure that each driver gets all the power it can handle. You can incorporate predetermined equalization and processing to help optimize performance and extend response. And since each driver is powered with just the frequency range it reproduces, you can kiss off the power-sucking, distortion-inducing passive crossover network required by virtually every conventional speaker. Active speakers have liabilities, too, but the situation mostly boils down to this: They're hard to sell. For whatever reasons, Americans like to choose their speakers and receivers (or amplifiers) independently. SETUP: Initial placement of the XF-48s was a mere matter of wrestling them out of their l-o-o-o-ng boxes and putting them 9 feet apart and 8 feet from my listening position. Hookup was simple: A line-level (RCA-plug) cable went from each speaker to my preamp/processor's line outputs, and wall current was delivered via the supplied removable power cords.

Klipsch began making high-performance speakers well before the advent of the transistor, so when it unveils an all-new flagship design, the world pays attention. Topping the company's Icon line, the XF-48 is a departure for Klipsch for several reasons. It's slim and very well dressed, with a gloss-lacquer finish and compound-curving "cheekbone" angles to its aluminum enclosure. It has a pair of oval passive-radiator diaphragms (no doubt in the interest of the aforementioned slimness). And it boasts an all-new horn-tweeter design. Most unusual of all, the XF-48 is an active full-range speaker - which means that all of the necessary amplification, custom tailored to its woofers and tweeter, is contained within the speaker itself.

Any engineer (or Vulcan) will tell you that active is the only logical speaker design. The advantages are many. Without wasting silicon (or dollars) on excess, you can ensure that each driver gets all the power it can handle. You can incorporate predetermined equalization and processing to help optimize performance and extend response. And since each driver is powered with just the frequency range it reproduces, you can kiss off the power-sucking, distortion-inducing passive crossover network required by virtually every conventional speaker. Active speakers have liabilities, too, but the situation mostly boils down to this: They're hard to sell. For whatever reasons, Americans like to choose their speakers and receivers (or amplifiers) independently.

SETUP

Initial placement of the XF-48s was a mere matter of wrestling them out of their l-o-o-o-ng boxes and putting them 9 feet apart and 8 feet from my listening position. Hookup was simple: A line-level (RCA-plug) cable went from each speaker to my preamp/processor's line outputs, and wall current was delivered via the supplied removable power cords.

There are speaker-level inputs (in case your processor or receiver lacks preamp outputs) plus mini toggles for high/low-input sensitivity and to enable the Icon's auto on/off circuitry. There's no way to individually balance the XF-48's low- and high-frequency amps - perfectly sensible, since unlike "power tower" designs with active-subwoofer-only sections, the Icon's low-frequency side covers the full bass-to-midrange spectrum.

The new tweeter horn (with integral lens or waveguide) has a claimed 80° x 80° dispersion pattern, and the horn's unusual, petal-like form serves a 3?4-inch compression driver - essentially, a tweeter engineered to mate with a horn. A controlled, consistent sound spread is the hallmark of horns, and the XF-48's output was indeed impressively even over a substantial horizontal range, maybe as much as 30°. The vertical sweet spot was a lot narrower - no doubt due to the drivers in the dual-midwoofer array being placed one above the other, an arrangement that's well known to restrict vertical dispersion, thereby reducing primary reflections.

Fine-tuning the placement of the Icons took a bit more work than I'd anticipated. I started out with the speakers hard against the wall behind them, with their grilles more or less on the same plane as my Samsung LCD TV. This seemed logical enough for a speaker that, visually at least, appears designed to match flat-panel TVs. But the sonic result was subpar: Bass was ample but a bit muddy and ill-defined, and there was a boosted, slightly tubby cast to male vocals - precisely what I'd expect from any conventional floorstanding speaker thus located.

Since I knew this couldn't be what Klipsch had in mind, I pulled out the Icons a couple of feet from the wall. Big improvement, though still a bit thick through the octave from the upper bass to the lower mids. So I pulled them out another 18 inches. Now we're talking!